#!/usr/bin/python
# -*- coding: utf8 -*-

def fib(n):
    """ Recursion """
    # 递归结束条件: n为0或1
    if(n == 0):
        return 0
    elif(n == 1):
        return 1
    else:
        return fib(n-1)+fib(n-2)   # 递归调用
